PrimeCo Personal Communications, L.P. (later known as Chicago 20 MHz, LLC) was a joint venture of Bell Atlantic, Nynex, US West and AirTouch Communications, and was the first wireless telecommunications provider to turn up CDMA service on the PCS (1900-MHz) band in late 1995. When the company was founded, it had its headquarters in Westlake, Texas. At a later point its headquarters were in Itasca, Illinois.Hailed as the largest wireless phone service launch in U.S.